Read line from text file into an array 1

[adrianjohnson]

I'm fairly new to Java, and looked on the net, but the read from file code I've seen do nothing with the input. What I'd like to do is read a line from a text file, pop it in an array, and then process it later on.

The code I've done is:

String record = null;
int recCount = 0;
int noRec = 0;

// Get the number of lines to process, so the array can be built.
// Is there a better way of doing this?
try
{
FileReader fr = new FileReader("rem.txt");
BufferedReader br = new BufferedReader(fr);

record = new String();
while ((record = br.readLine()) != null)
{
recCount++;
}
}
catch (IOException e)
{
// catch possible io errors from readLine()
System.out.println("Error reading from the file!");
e.printStackTrace();
}

// Create array based on number of lines in text file.
noRec = recCount;
String[] remLine = new String[noRec];

// Read each line, and add to array.
try
{
FileReader fr2 = new FileReader("rem.txt");
BufferedReader br2 = new BufferedReader(fr2);

recCount = 0;
noRec = 0;
while ((remLine[noRec] = br2.readLine()) != null)
{
System.out.println(recCount + ": " + remLine[noRec]);
recCount++;
}
}
catch (IOException e)
{
// catch possible io errors from readLine()
System.out.println("Error reading from the file!");
e.printStackTrace();
}

// This line not working properly, as it returns null.
System.out.println(remLine[noRec]);

// How do I process what's in remLine here????


Thanks,

Adrian Johnson

Adrian Johnson
Assystance - i.t. solutions

http://www.assystance.com

 

[sedj]

I think you are going around this in a bit of a daft way ... you really shouldn't read the files twice just to see how many lines there are ...

ArrayList al = new ArrayList();
BufferedReader br = new BufferedReader(new FileReader("C:/ll_output"));
String line = "";
while ((line = br.readLine()) != null) {
  al.add(line);
}

Object[] array = al.toArray();

 

[javaken]

This will be something like this ......

Greetings

/*
* Created on 21-mei-2004
*
*/


import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;


public class ReadingFile {
public ReadingFile(String tempFile) throws IOException{

File f = new File(tempFile);
ArrayList al = new ArrayList();
BufferedReader br = new BufferedReader(new FileReader(f));
String line = "";
while ((line = br.readLine()) != null) {
al.add(line);
}

Object[] array = al.toArray();

System.out.println("Object:");
for (int count = 0; count < array.length; count++)
System.out.println(array[count]);

}

public static void main(String args[]) throws IOException
{
ReadingFile rfObj = new ReadingFile("Rem.txt");
}

}

 

[sedj]

javaken :

Is this not what I posted ??!!!

 

[javaken]

Your code/solution was very nice Sedj!!!!!!

I complete it because it was so nice ! It's above so short.

Thanks Sedj!!!!

 

[adrianjohnson]

Sorry for the dense question, but as I said "I'm fairly new to Java"!!

Anyway, is there a declaration I need for ArrayList, as I'm getting an error saying it cannot be resolved or is not a type.

Adrian Johnson
Assystance - i.t. solutions

http://www.assystance.com

 

[adrianjohnson]

I posted my reply before refreshing the page!! I'll read the posts/code and see what happens.



Adrian Johnson
Assystance - i.t. solutions

http://www.assystance.com

 

[sedj]

As javaken's version points out in the "import" statements, ArrayList is in the package "java.util" ...

 

[adrianjohnson]

I'm getting an error on the while loop:

"Syntax error on keyword "while"; "boolean", "void", "byte", "short", "int", "long", "char", "float", "double", "Identifier", "interface", "class" expected"

Mean anything??


Adrian Johnson
Assystance - i.t. solutions

http://www.assystance.com

 

[sedj]

post the exact code ... the examples I and javaken have posted work ok ...

 

[adrianjohnson]

This is the complete code. Loads of other stuff, to do with frames etc., but at least you'll see what I'm doing with it.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

public class Breaktime extends JMenuBar
{
	String[] fileItems = new String[] { "Exit" };
	String[] remItems = new String[] { "Administer" };
	String[] helpItems = new String [] { "About..."	};
	char[] fileShortcuts = { 'X' };
	char[] remShortcuts = { 'A'	};
	char[] helpShortcuts = { 'B' };
	
	
	public Breaktime()
	{
		
		JMenu fileMenu = new JMenu("File");
		JMenu remMenu = new JMenu("Reminder");
		JMenu helpMenu = new JMenu("Help");
		
		// Assemble the File menu.
		ActionListener printListener = new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{
				System.out.println("Menu item pressed.");		
			}
		};
		
		for (int i=0; i<fileItems.length;i++)
		{
			JMenuItem item = new JMenuItem(fileItems[i], fileShortcuts[i]);
			item.setAccelerator(KeyStroke.getKeyStroke(fileShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
			item.addActionListener(printListener);
			fileMenu.add(item);
		}
		
		// Assemble the Reminder menu.
		for (int i=0; i<remItems.length; i++)
		{
			JMenuItem item = new JMenuItem(remItems[i]);
			item.setAccelerator(KeyStroke.getKeyStroke(remShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
			item.addActionListener(printListener);
			remMenu.add(item);
		}
		
		// Assemble the Reminder menu.
		for (int i=0; i<helpItems.length; i++)
		{
			JMenuItem item = new JMenuItem(helpItems[i]);
			item.setAccelerator(KeyStroke.getKeyStroke(helpShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
			item.addActionListener(printListener);
			helpMenu.add(item);
		}
		
		// Add the menus to the menu bar.
		add(fileMenu);
		add(remMenu);
		add(helpMenu);
	}
	
	public void actionPerformed(ActionEvent event)
	{
		//dispose();
		System.exit(0);
	}
	
	
	public static void main(String[] args)
	{
		Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
		int x = (screen.width-400)/2;
		int y = (screen.height-300)/2;
		
		SplashScreen splash = new SplashScreen(3000);
		splash.showSplash();
				
		JFrame frame = new JFrame("Breaktime - reminders program.");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setJMenuBar(new Breaktime());
		frame.pack();
		frame.setBounds(x,y,400,300);
		
		Toolkit tk = Toolkit.getDefaultToolkit();
		Image img = tk.getImage("icon.gif");
		frame.setIconImage(img);
		
		frame.setVisible(true);
		frame.setState ( Frame.ICONIFIED );
		
		ImageIcon icon = new ImageIcon("title.png");
		JLabel l = new JLabel(icon);
		l.setBounds(0,0,icon.getIconWidth(), icon.getIconHeight());
		frame.add(l);
		
		/*
		File f = new File("rem.arf");
		ArrayList al = new ArrayList();
		BufferedReader br = new BufferedReader(new FileReader(f));
		String line = "";
		while ((line = br.readLine()) != null)
		{
			al.add(line);
		}

		Object[] array = al.toArray();
    
		System.out.println("Object:");
		for (int count = 0; count < array.length; count++)
			System.out.println(array[count]);
*/
		

	}

}

 

[sedj]

compiles fine for me ... are you using javac to compile it ?

 

[adrianjohnson]

No, Eclipse. You'll need to un-comment your code though (unless you did that and it worked!). I commented it out to test something else, and forgot to uncomment it.


Adrian Johnson
Assystance - i.t. solutions

http://www.assystance.com

 

[sedj]

OK, uncommented code, but still cannot find any real problem - apart from :

This :
frame..add(l);
should be :
frame.getContentPane().add(l);

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

public class Breaktime extends JMenuBar
{
    String[] fileItems = new String[] { "Exit" };
    String[] remItems = new String[] { "Administer" };
    String[] helpItems = new String [] { "About..."    };
    char[] fileShortcuts = { 'X' };
    char[] remShortcuts = { 'A'    };
    char[] helpShortcuts = { 'B' };
    
    
    public Breaktime()
    {
        
        JMenu fileMenu = new JMenu("File");
        JMenu remMenu = new JMenu("Reminder");
        JMenu helpMenu = new JMenu("Help");
        
        // Assemble the File menu.
        ActionListener printListener = new ActionListener()
        {
            public void actionPerformed(ActionEvent event)
            {
                System.out.println("Menu item pressed.");        
            }
        };
        
        for (int i=0; i<fileItems.length;i++)
        {
            JMenuItem item = new JMenuItem(fileItems[i], fileShortcuts[i]);
            item.setAccelerator(KeyStroke.getKeyStroke(fileShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
            item.addActionListener(printListener);
            fileMenu.add(item);
        }
        
        // Assemble the Reminder menu.
        for (int i=0; i<remItems.length; i++)
        {
            JMenuItem item = new JMenuItem(remItems[i]);
            item.setAccelerator(KeyStroke.getKeyStroke(remShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
            item.addActionListener(printListener);
            remMenu.add(item);
        }
        
        // Assemble the Reminder menu.
        for (int i=0; i<helpItems.length; i++)
        {
            JMenuItem item = new JMenuItem(helpItems[i]);
            item.setAccelerator(KeyStroke.getKeyStroke(helpShortcuts[i],Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(),false));
            item.addActionListener(printListener);
            helpMenu.add(item);
        }
        
        // Add the menus to the menu bar.
        add(fileMenu);
        add(remMenu);
        add(helpMenu);
    }
    
    public void actionPerformed(ActionEvent event)
    {
        //dispose();
        System.exit(0);
    }
    
    
    public static void main(String[] args)
    {
        Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
        int x = (screen.width-400)/2;
        int y = (screen.height-300)/2;
        
        SplashScreen splash = new SplashScreen(3000);
       splash.showSplash();
                
        JFrame frame = new JFrame("Breaktime - reminders program.");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setJMenuBar(new Breaktime());
        frame.pack();
        frame.setBounds(x,y,400,300);
        
        Toolkit tk = Toolkit.getDefaultToolkit();
        Image img = tk.getImage("icon.gif");
        frame.setIconImage(img);
        
        frame.setVisible(true);
        frame.setState ( Frame.ICONIFIED );
        
        ImageIcon icon = new ImageIcon("title.png");
        JLabel l = new JLabel(icon);
        l.setBounds(0,0,icon.getIconWidth(), icon.getIconHeight());
        frame.getContentPane().add(l);
        
        
        File f = new File("rem.arf");
        ArrayList al = new ArrayList();
  	try {
        	BufferedReader br = new BufferedReader(new FileReader(f));
        	String line = "";
        	while ((line = br.readLine()) != null) {
            		al.add(line);	
		}
	} catch (IOException ioe) {
		ioe.printStackTrace(System.err);
	}

        Object[] array = al.toArray();
    
        System.out.println("Object:");
        for (int count = 0; count < array.length; count++)
            System.out.println(array[count]);

        

    }

}